Spice Health Research, With Citations

Plenty of sites list spice health benefits with no source behind them. This page does the opposite: every claim below names the review it came from and links to it, so you can check the evidence rather than take our word for it.

How claims are chosen

• Human trials only, pooled in a systematic review or meta-analysis. Cell studies and animal studies aren't included, because they rarely predict what happens in people.
• Recent reviews, and each one is read before use rather than trusted from its title. One garlic meta-analysis was excluded because PubMed flags it as retracted, and one apparent sage result turned out to be a paper from SAGE the publisher, with nothing to do with the herb.
• Results as the authors reported them, including the findings that showed no effect, and including the authors' own warnings about study quality.
• No claim without a citation. If we can't link the research, the claim doesn't go on the page.

Research summaries here are drawn from PubMed. Each entry links to the original article by DOI.

The research, spice by spice

• Ginger

  Zingiber officinale · Nausea and vomiting

  • Ginger reduced nausea scores more than conventional medicine in pregnancy, and beat placebo on the share of people who improved. The reviewers rated this moderate-quality evidence for the nausea score and low-quality for the rest.

    Source: Tan MY and colleagues, a 2023 systematic review and meta-analysis of 33 randomized trials in Frontiers in Public Health. DOI 10.3389/fpubh.2023.1108756

  • For chemotherapy-related sickness, ginger did not significantly change rates of nausea or delayed vomiting overall. One subgroup, up to 1 g a day for more than four days, had less acute vomiting than controls.

    Source: Choi J and colleagues, a 2022 systematic review of 23 randomized trials in Nutrients. DOI 10.3390/nu14234982

  Worth knowing: Pregnancy and cancer treatment are both situations where you should talk to your own clinician before adding a supplement.

• Turmeric

  Curcuma longa, studied as curcumin · Knee osteoarthritis

  • Curcumin reduced knee pain scores and total WOMAC scores compared with placebo, and had fewer adverse reactions than non-steroidal anti-inflammatory drugs.

    Source: Zhao J and colleagues, a 2023 Bayesian network meta-analysis of 23 trials and 2,175 patients in the Journal of Ethnopharmacology. DOI 10.1016/j.jep.2023.117493

  Worth knowing: These trials used concentrated curcumin supplements, not the amount of turmeric you would put in a curry. The doses aren't comparable.

• Cinnamon

  Cinnamomum species · Blood sugar in type 2 diabetes

  • Cinnamon supplementation significantly lowered fasting blood sugar, insulin resistance scores, and HbA1c compared with control groups. Serum insulin did not change significantly. The authors describe it as possible adjunct support, not a replacement for treatment.

    Source: Moridpour AH and colleagues, a 2023 systematic review and dose-response meta-analysis of 24 randomized trials in Phytotherapy Research. DOI 10.1002/ptr.8026

  Worth knowing: This research is about supplements taken by people being treated for type 2 diabetes. Never change diabetes medication based on a spice.

• Garlic

  Allium sativum · Metabolic syndrome markers

  • Garlic supplementation reduced triglycerides, total cholesterol, LDL cholesterol, diastolic blood pressure, BMI, and waist circumference compared with placebo. The authors note high variation between studies and possible publication bias, and call for larger trials.

    Source: Fu Z and colleagues, a 2023 systematic review and meta-analysis of 19 randomized trials in BMC Complementary Medicine and Therapies. DOI 10.1186/s12906-023-04038-0

  Worth knowing: Garlic supplements can interact with blood-thinning medication. Check with a pharmacist or doctor before taking them.

• Peppermint

  Mentha piperita, studied as peppermint oil · Irritable bowel syndrome

  • Peppermint oil beat placebo for overall IBS symptoms and for abdominal pain, with about 4 people needing treatment for one to improve. Side effects, mainly reflux, were significantly more common than with placebo, and the reviewers rated the quality of evidence very low.

    Source: Ingrosso MR and colleagues, a 2022 systematic review and meta-analysis of 10 randomized trials and 1,030 patients in Alimentary Pharmacology & Therapeutics. DOI 10.1111/apt.17179

  Worth knowing: This research used enteric-coated peppermint oil capsules at controlled doses, not peppermint tea or fresh leaves. Peppermint oil can worsen reflux.

• Saffron

  Crocus sativus · Depression and anxiety

  • Across 8 trials, saffron and SSRI antidepressants produced no significant difference in depressive symptoms, and across 4 trials no significant difference in anxiety symptoms. People taking saffron had fewer adverse events. The authors call for larger trials before drawing firm conclusions.

    Source: Shafiee A and colleagues, a 2024 meta-analysis of randomized controlled trials in Nutrition Reviews. DOI 10.1093/nutrit/nuae076

  • Saffron supplementation also lowered fasting blood glucose and HbA1c in a separate review that looked at blood sugar.

    Source: Correia AGS and colleagues, a 2023 systematic review and meta-analysis of 19 studies in Phytotherapy Research. DOI 10.1002/ptr.7817

  Worth knowing: No difference from an antidepressant in a trial is not a reason to stop or replace prescribed medication. That is a conversation for your doctor.

• Fenugreek

  Trigonella foenum-graecum · Blood sugar

  • Fenugreek lowered fasting blood glucose, post-meal blood glucose, and HbA1c compared with controls. The authors note high variation between studies for the first two measures and ask for higher-quality trials.

    Source: Correia AGS and colleagues, a 2023 systematic review and meta-analysis of 19 studies in Phytotherapy Research. DOI 10.1002/ptr.7817

  Worth knowing: As with cinnamon, this is research on supplements alongside treatment, not a reason to change diabetes medication.

• Chili pepper

  Capsicum species, studied as capsaicin · Body weight

  • Capsaicin supplementation produced small reductions in BMI, body weight, and waist circumference in overweight and obese adults. The authors describe the effects as rather modest: about half a kilogram of body weight on average. Waist-to-hip ratio did not change.

    Source: Zhang W and colleagues, a 2023 systematic review and meta-analysis of 15 randomized trials and 762 people in the British Journal of Nutrition. DOI 10.1017/S0007114523000697

  Worth knowing: Half a kilogram across a whole study is not a weight-loss plan. This is a small effect from a supplement, not from seasoning your food.

• Black seed

  Nigella sativa · Blood sugar and cholesterol

  • In people with type 2 diabetes, black seed supplementation lowered fasting blood glucose, HbA1c, total cholesterol, and LDL cholesterol. It showed no significant effect on post-meal glucose, fasting insulin, triglycerides, HDL, liver enzymes, kidney function, body weight, or BMI.

    Source: Karimi M and colleagues, a 2025 systematic review and meta-analysis of 16 randomized trials in Complementary Therapies in Medicine. DOI 10.1016/j.ctim.2025.103174

  Worth knowing: The authors describe it as possible adjunct support alongside treatment, not a replacement for it.

• Black pepper

  Piper nigrum, studied as piperine · Absorption of curcumin, inflammation markers

  • Piperine is used in trials to raise how much curcumin the body absorbs, because curcumin on its own is poorly absorbed. Taking the two together increased antioxidant enzyme activity and lowered markers of oxidative stress and inflammation, including TNF-alpha and IL-6.

    Source: Hosseini H and colleagues, a 2025 systematic review and meta-analysis of 13 randomized trials in Current Medicinal Chemistry. DOI 10.2174/0109298673260515240322074849

  Worth knowing: The widely repeated claim that black pepper raises curcumin absorption by 2,000% traces to a single small 1998 study, not to this review. Piperine also affects how the body processes some medicines, so check with a pharmacist if you take any.

• Cardamom

  Elettaria cardamomum · Blood sugar and weight

  • Three grams a day for 8 weeks to 3 months produced no significant change in BMI, body weight, waist circumference, fasting blood sugar, or insulin. It did significantly improve insulin resistance scores and HbA1c. Only six trials and 410 people have been studied.

    Source: Nameni G and colleagues, a 2022 systematic review and meta-analysis of 6 randomized trials in Diabetes & Metabolic Syndrome. DOI 10.1016/j.dsx.2022.102523

  Worth knowing: This is a small evidence base, and most of the measures showed no effect. Treat it as preliminary.

• Rosemary, thyme, oregano, basil, clove, and parsley

  Six Mediterranean herbs and spices, grouped · Blood sugar: no significant effect

  • A 2024 review set out to test 12 herbs and spices from the Mediterranean diet for their effect on blood sugar in people with type 2 diabetes. Only five improved fasting glucose: cinnamon, turmeric, ginger, black cumin, and saffron. Rosemary, thyme, oregano, basil, clove, and parsley did not. Only ginger and black cumin improved HbA1c, and only cinnamon and ginger lowered insulin.

    Source: Garza MC and colleagues, a 2024 systematic review and meta-analysis of 45 studies in Nutrients. DOI 10.3390/nu16060756

  Worth knowing: A null result is still a result. These herbs are worth using for flavor; the trials just don't support a blood sugar claim for them.

• Sage

  Salvia officinalis · Menopausal hot flashes

  • Across four trials and 310 women, sage significantly reduced how often hot flashes happened compared with placebo, but the reduction in how severe they were was not statistically significant. Variation between studies was high, and the authors call for further investigation before recommending wider use.

    Source: Moradi M and colleagues, a 2023 systematic review and meta-analysis in the International Journal of Community Based Nursing and Midwifery. DOI 10.30476/IJCBNM.2023.97639.2198

  Worth knowing: Four small trials is a thin evidence base, and the same 2024 Mediterranean review found no blood sugar effect for related kitchen herbs. Menopause treatment is worth discussing with a doctor.

• Nutmeg

  Myristica fragrans · Nerve pain: no meaningful effect found

  • A Cochrane review of herbal products for neuropathic pain found only two eligible trials in total, one of them a topical nutmeg spray. Nutmeg showed no evidence of a difference from placebo on pain relief, and the reviewers rated the evidence very low quality, concluding there was insufficient evidence to determine whether it has any meaningful effect.

    Source: Boyd A and colleagues, a 2019 Cochrane systematic review in the Cochrane Database of Systematic Reviews. DOI 10.1002/14651858.CD010528.pub4

  Worth knowing: Nutmeg is genuinely toxic in large amounts. This is one reason to treat it as a flavoring rather than a remedy.

Why some spices aren't here

This page covers every common culinary spice with a published systematic review or meta-analysis of human trials behind it. That's the honest limit of the list: coriander, bay, and star anise were all searched for and returned no qualifying review, so they have no entry rather than an invented one.

It will grow as research is published. If you know of a review that belongs here, or spot one that has been retracted or superseded, send it through the contact page and it will be checked.

Where the research doesn't support a popular claim, the page will say so rather than leave the claim out quietly.

Looking for flavor instead?

If you came here to cook rather than to read research, the Global Spice Blend Explorer covers 75 blends by region, and the seasonal spice guide sorts 95 spices and herbs by season.